Finally Answered!! Out of Date Airbags
Just got the call from Mercedes Canada airbag compliance on what happens if you leave an out of date airbag in your car.
1) There is no danger of accidental deployment.
2) It should be replaced to ensure proper deployment in case of accident. If it is not replaced - the worst that can happen is that it will only partially deploy or not deploy at all which could cause injury in case of an accident.
SO TO PUT IT IN A NUTSHELL - IF YOUR AIRBAG IS OVER 15 YEARS OLD AND YOU DON'T CARE IF IT DEPLOYS IN AN ACCIDENT - LEAVE IT - MERCEDES WON'T BE RESPONSIBLE FOR ANY INJURIES. THE OFFICIAL LINE IS "IF IT OVER 15 YEARS OLD - CHANGE IT WITH A NEW ONE."